66 
attached to the top of a papilla, while the adjacent carpogonium has divided by a 
transverse wall after fecundation; the fertilization-canal of this carpogonium is yet 
to be seen below. The carpogonia produce 4 or 8 spores in two layers. 
This species seems to disappear during the summer. On July 22¢ 1905 on 
the moles of the harbour of Skagen I only found some very small specimens 1— 
1,5 cm. high, being evidently the under part of specimens which had exhausted 
their spermatia and carpospores; there were namely still to be seen remnants of 
emptied antheridial sori and some few cystocarps containing 8 spores, while the 
upper border of the frond consisted of emptied cell-walls (Plate II fig. 9—13). In 1907 
the species remained longer, perhaps in connection with the fact, that the summer 
was unusually cold with predominant westerly winds. On July 11% 1907 I found 
in the same locality rather large specimens, some of which showed antheridia, 
in part not emptied, and cystocarps. Other specimens did not show these organs 
and did not seem to have produced them earlier. In such a specimen the cells in 
the upper part of the frond had more granular contents than the vegetative cells, 
for which reason I am inclined to believe, that they were producing gonidia (Plate II 
fig. 8). These cells had a sharply limited lateral vacuole; they were not divided by 
walls parallel to the frond. 
Kyrın (1907 p. 110 Taf. 3 Fig. 1) has established a species nearly related to 
P. leucosticta under the name P. elongata (Aresch.) Kyrın (P. laciniata var. Areschoug 
Alg. Scand. exsicc. No. 117), which is distinguished by its elongated form of frond 
with uniform breadth, its thinner frond (25—33 y while it is said to be 33—40 u 
in P. leucosticta), and the smaller antheridial sori; it may be added that the 
author found it epiphytic and fructiferous in August. It appears to me, however, 
to be rather doubtful if it can really be regarded as a species distinct from P. leu- 
costicta; at all events, the alleged characters are hardly conclusive. As said above 
P. leucosticta has often a lingulate form (comp. PI. II fig. 4—8), and that is so also 
in specimens from the coasts of France. The thickness of the frond was found, in 
the Danish specimens of this species, to vary on both sides of the limit given by 
Kyrın (se above). That the sori of antheridia in the specimens of KyLiN reached 
only a size of 2 mm., while they attained a length of 10 mm. in the Danish spe- 
cimens, is scarcely sufficient for specific distinction. I have found no specimen on 
the Danish coasts fully agreeing with P. elongata Kyrın, the specimen most similar 
to it was 16 cm. long, 2 cm. broad, on the one side with a small lobe; it had a 
thickness of 28 », but the antheridial sori .were long. 
The plant grows on stones at the mean level of the sea. 
Localities. Sk: Hirshals, on the mole and: on a large boulder on the shore, April 1906. — 
Kn: Harbour of Skagen; it appeared contemporaneously with the construction of the harbour; it was 
detected by Mag. M. L. MORTENSEN, “/4 1905, on the moles commenced the preceding year and constructed, 
as far as known, exclusively of stones taken on land. Later, I have found it, on several visits in April 
and July, on the outer and inner sides of the moles, but only or principally near land. 
